Image enhancement can improve the quality of life of elderly, visually impaired persons through the use and enjoyment of images in print or video form. Image enhancement should provide improved access to the television medium and is a necessary component in the design of a new generation of electronic mobility aids. This study is aimed at designing and evaluating practical image-enhancement methods. The investigation approaches this problem on three different levels. The first approach is to develop a systematic (model-driven) method for optimal, individually tuned image enhancement for the visually impaired. This will be achieved by studying the various parameters affecting image recognition in enhanced images viewed by normal and low-vision observers. This aspect of the study will be carried out using monochrome, still, face images that enable careful quantitative evaluation of the effects. The second aspect of the investigation, which supports the first one, is a basic study of the perception of contrast by normal and impaired observers. This study involves the development of a valid metric for contrast in complex images, and the determination of the contrast sensitivity function and image characteristics that are relevant to the analysis and modeling of spatial vision. Parallel to these basic studies, the third aspect of the investigation involves the evaluation of existing enhancement technologies in improving the visibility of details from color, motion video segments. This study should provide a better understanding of the type of visual details that are missed by patients with various visual disabilities, and a measure of the improvement obtained with technology that already exists for enhancement in real-time of such images. In addition to exploring a specific visual-aid technology, the results of this study will increase our understanding of the nature of vision loss and its effects on perception. Such knowledge is useful in many aspects of vision rehabilitation.